WO2020105099A1

WO2020105099A1 - Communication system, communication device, communication method, and program

Info

Publication number: WO2020105099A1
Application number: PCT/JP2018/042727
Authority: WO
Inventors: 克洋安念; 大祐竹内
Original assignee: 三菱電機株式会社
Priority date: 2018-11-19
Filing date: 2018-11-19
Publication date: 2020-05-28
Also published as: US20210392209A1; DE112018008145T5; JP6570804B1; JPWO2020105099A1; TW202021327A; TWI699105B; US11528348B2

Abstract

A communication system (1000) comprises a master device (10) and a slave device (30) which perform, at predetermined periods, communication for sharing stored data stored in a cyclic memory (41). Communication data transmitted by the master device (10) includes: identifying information identifying a period relating to the communication data from other periods before and after the period relating to the communication data; and relevance information indicating whether the communication data is relevant for the periodical communication or irrelevant and should be excluded from the periodical communication. The slave device (30) discards the communication data if the relevance information included in the communicated and received communication data indicates that the communication data is relevant and if the period indicated by the identifying information included in the communication data differs from the period of the current period. The slave device (30) processes the communication data if the relevance information included in the communication data indicates that the communication data is irrelevant and if the period indicated by the identifying information included in the communication data differs from the current period.

Description

Communication system, communication device, communication method, and program

The present invention relates to a communication system, a communication device, a communication method, and a program.

At facilities represented by factories, a system that controls multiple devices via a communication network is in operation. Such a system is required to allow a plurality of devices to cooperate efficiently. Therefore, there is a case where so-called cyclic communication is adopted in which common data is stored in the memory of each device. In the cyclic communication, communication for sharing the content of the area allocated to each device in the memory with other devices is periodically executed.

In cyclic communication, each device normally communicates with each cycle to synchronize the data stored in the memory with each successive cycle. Here, the cycle information for identifying the cycle relating to the data may be added to the data transmitted between the devices (for example, see Patent Document 1).

Patent Document 1 describes a cyclic communication system in which a plurality of terminals perform cyclic communication via a network. In this cyclic communication system, when the cyclic communication data is divided into a plurality of data and transmitted, a counter value counted for each cycle of the cyclic communication is added to each data. Then, the terminal receiving the divided data refers to the counter value, so that the simultaneity with respect to the plurality of divided data is secured.

JP, 2005-82271, A

In cyclic communication, it is necessary to perform communication for synchronizing data within each cycle. When data including cycle information is transmitted as exemplified in the technique of Patent Document 1, the device receiving the data sets the cycle indicated by the cycle information as the current cycle internally managed. It is possible to collate. Then, when the cycles match, the device determines that the received data is valid and processes it, and when the cycles are different, it determines that the received data is invalid and discards it. As a result, common data can be managed on the transmitting side and the receiving side as data to be transmitted in each cycle.

However, when the first device that communicates at high speed and the second device that communicates at low speed coexist, there is a possibility that communication in each cycle of the second device may not be completed. Specifically, when the data to be transmitted in one cycle is not received within the period of the one cycle and is received in the next cycle, the data is not processed, and as a result, Data that should be stored in memory may not be stored. Therefore, in order to complete the communication in each cycle, it is necessary to reduce the speed of the device that communicates at high speed to operate, or replace the device that communicates at low speed with a high-performance device. Therefore, it is not possible to utilize the communication performance while mixing the devices having different communication performances, and there is a room for improving the efficiency of the communication system.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the efficiency of a communication system.

In order to achieve the above object, the communication system of the present invention is a communication including a first communication device and a second communication device that performs communication for sharing storage data stored in a storage unit at each predetermined cycle. In the system, the communication data transmitted by the first communication device includes identification information that identifies a cycle relating to the communication data from other cycles before and after the cycle, and the communication data is a target of communication for each cycle. Target information indicating whether the communication data is an exception or an exception excluded from the target, the second communication device receives the communication data, and the communication data is targeted by the target information included in the received communication data. Is indicated and the cycle indicated by the identification information included in the communication data is different from the current cycle, the communication data is discarded, and the communication data is an exception due to the target information included in the communication data. Communication data is processed.

According to the present invention, the second communication device receives the communication data, indicates that the communication data is the target by the target information included in the received communication data, and uses the identification information included in the communication data by the target information. When the indicated cycle is different from the current cycle, the communication data is discarded, and when the target information included in the communication data indicates that the communication data is an exception, the communication data is processed. Therefore, the communication performance can be utilized while the devices having different communication performances are mixed, and the efficiency of the communication system can be improved.

The figure which shows the structure of the communication system which concerns on embodiment of this invention. The figure which shows the cyclic memory which concerns on embodiment. The figure which shows the communication for every period by the communication apparatus which concerns on embodiment. The figure which shows the hardware constitutions of the communication apparatus which concerns on embodiment. The figure which shows the functional structure of the communication apparatus which concerns on embodiment. Flowchart showing master processing according to an embodiment Flowchart showing slave processing according to the embodiment Flowchart showing master initialization processing according to the embodiment FIG. 6 is a diagram showing a format of a frame transmitted in the master initialization process according to the embodiment. Flowchart showing slave initialization processing according to the embodiment FIG. 3 is a diagram showing a format of a frame transmitted in the slave initialization process according to the embodiment. FIG. 1 is a first diagram showing an example of communication processing according to an embodiment. 2nd figure which shows an example of the communication processing which concerns on embodiment Flowchart showing master communication processing according to the embodiment The figure which shows the format of the frame transmitted in the master communication process which concerns on embodiment. 3rd figure which shows an example of the communication processing which concerns on embodiment The figure which shows an example of the communication processing which concerns on a comparative example. The figure which shows an example of the communication processing which concerns on a modification.

Hereinafter, a communication system 1000 according to an embodiment of the present invention will be described in detail with reference to the drawings.

Embodiment.
Communication system 1000 according to the present embodiment corresponds to a part of FA system installed in a factory. The communication system 1000 is formed by connecting devices constituting a FA system, such as a production system, an inspection system, a processing system, and other systems, via a communication path. As shown in FIG. 1, the communication system 1000 includes a master device 10 and

slave devices

21, 22, 30 as communication devices.

The master device 10 and the

slave devices

21, 22, 30 are, for example, a PLC (Programmable Logic Controller), a device that works with the PLC, or an IPC (Industrial Personal Computer). The master device 10 and the

slave devices

21, 22, 30 are connected to each other via a communication network 50. The communication network 50 is, for example, a field network formed by a network cable.

The master device 10 corresponds to a master node of the communication system 1000, and the

slave devices

21, 22, 30 correspond to slave nodes of the communication system 1000, respectively. The master device 10 transmits a control instruction to the

slave devices

21, 22, 30 via the communication network 50. Each of the

slave devices

21, 22 and 30 controls a device (not shown) connected to itself, according to a control instruction. This device is, for example, a sensor device, an actuator, or a robot.

The master device 10 and the

slave devices

21, 22, 30 each have a cyclic memory 41 in which common data is stored. The cyclic memory 41 includes a storage area assigned to each communication device. Specifically, as shown in FIG. 2, the cyclic memory 41 has a storage area A10 assigned to the master device 10, a storage area A21 assigned to the slave device 21, and a storage assigned to the slave device 22. It has an area A22 and a storage area A30 assigned to the slave device 30. Each of these storage areas stores data updated by the assigned communication device. For example, the storage area A10 stores data updated by the master device 10, and the data stored in the storage area A10 is not updated by the

slave devices

21, 22, 30. The cyclic memory 41 is an example of a storage unit that stores data shared by the master device 10 and the

slave devices

21, 22, 30. Hereinafter, the data stored in the cyclic memory 41 will be referred to as stored data.

The master device 10 and the

slave devices

21, 22, 30 carry out cyclic communication for sharing the storage data stored in the cyclic memory 41 for each predetermined cycle. FIG. 3 exemplifies such communication. However, in FIG. 3, the slave device 21 is shown as a representative of the

slave devices

21 and 22, and the slave device 22 is omitted.

As shown in FIG. 3, in a cycle T1, each communication device transmits communication data for updating the contents of the cyclic memory 41. For example, the arrow 501 indicates that the master device 10 transmits communication data including data for updating the content of the storage area A10 to the

slave devices

21 and 30. Similarly, the

slave devices

21 and 30 also transmit communication data for updating the contents of the storage areas A21 and 30 to other communication devices in the cycle T1. The contents of the cyclic memory 41 are shared by all the communication devices by the end time of the cycle T1.

Communication similar to cycle T1 is performed in other cycles T2 and T3. The length of the cycles T1 to T3 is, for example, 1 microsecond or 1 millisecond. The cycles T1, T2 and T3 may be cycles defined by managing time by connecting a plurality of communication devices to an NTP (Network Time Protocol) server, or the master device 10 transmits communication data. It may be a cycle that starts each time. When the cycles T1, T2, T3 are started by transmission of communication data from the master device 10, the lengths of the cycles T1, T2, T3 may be different. In such a case, the

slave devices

21 and 30 may determine the current cycle by measuring the time elapsed from the start time of the previous cycle. Further, in this case, if the

slave devices

21 and 30 respond to the communication data transmitted from the master device 10 at a relatively high speed and transmit the communication data, the communication is completed within each cycle.

Here, the slave device 30 is a device that communicates at a lower speed than the

slave devices

21 and 22, and as shown by an arrow 503, transmission of communication data from the slave device 30 may not be completed within a cycle. .. The communication device according to the present embodiment treats the communication data thus transmitted as a target of cyclic communication for which communication should be completed in each cycle according to the content of the communication data, and discards or discards it. It is used for updating the cyclic memory 41 as an exception to the click communication.

The

slave devices

21 and 22 that communicate at a higher speed than the slave device 30 are, for example, devices that execute software processing with a high-performance processor. However, the

slave devices

21 and 22 may be devices that are hardware-implemented with dedicated communication circuit chips. The slave device 30 that communicates at a lower speed than the

slave devices

21 and 22 is, for example, a device that executes software processing with a low-performance processor. The master device 10 carries out the above-mentioned cyclic communication with the

slave devices

21 and 22, and carries out exceptional communication with the slave device 30 in which communication data transmitted is treated as an exception to cyclic communication. However, when the master device 10 itself is a device that communicates at low speed, the master device 10 performs exceptional communication with all the

slave devices

21, 22, and 30.

In the following, the master device 10 and the

slave devices

21, 22, 30 are collectively referred to as the communication device 40.

As shown in FIG. 4, the hardware configuration of the communication device 40 includes a processor 401, a main storage unit 402, an auxiliary storage unit 403, an input unit 404, an output unit 405, and a communication unit 406. Have. The main storage unit 402, the auxiliary storage unit 403, the input unit 404, the output unit 405, and the communication unit 406 are all connected to the processor 401 via the internal bus 407.

The processor 401 includes a CPU (Central Processing Unit). The processor 401 realizes various functions of the communication device 40 by executing the program P1 stored in the auxiliary storage unit 403, and executes the processing described below.

The main storage unit 402 includes a RAM (Random Access Memory). The program P1 is loaded from the auxiliary storage unit 403 into the main storage unit 402. The main storage unit 402 is used as a work area of the processor 401.

The auxiliary storage unit 403 includes a nonvolatile memory represented by an EEPROM (Electrically Erasable Programmable Read-Only Memory) and an HDD (Hard Disk Drive). The auxiliary storage unit 403 stores, in addition to the program P1, various data used for the processing of the processor 401. The auxiliary storage unit 403 supplies data used by the processor 401 to the processor 401 according to an instruction from the processor 401, and stores the data supplied from the processor 401.

The input unit 404 includes an input device represented by an input key and a pointing device. The input unit 404 acquires information input by the user of the communication device 40 and notifies the processor 401 of the acquired information.

The output unit 405 includes an output device represented by an LCD (Liquid Crystal Display) and a speaker. The output unit 405 presents various kinds of information to the user according to the instruction of the processor 401.

The communication unit 406 includes a network interface circuit for communicating with an external device. The communication unit 406 receives a signal from the outside and outputs the data indicated by this signal to the processor 401. The communication unit 406 also transmits a signal indicating the data output from the processor 401 to an external device.

The communication device 40 exerts various functions by the cooperation of the hardware configurations shown in FIG. In detail, as shown in FIG. 5, the communication device 40 has, as its functions, a cyclic memory 41, a communication interface 42 that transmits communication data to the communication network 50, and receives communication data from the communication network 50. A reception processing unit 43 that processes communication data received via the communication interface 42, and a transmission processing unit 44 that executes a process of transmitting communication data via the communication interface 42.

The cyclic memory 41 is mainly realized by the main storage unit 402. However, the invention is not limited to this, and the cyclic memory 41 may be realized by the auxiliary storage unit 403.

The communication interface 42 is realized by the communication unit 406. The communication interface 42 sends the communication data received from the communication network 50 to the reception processing unit 43, and sends the communication data sent from the transmission processing unit 44 to the communication network 50.

The reception processing unit 43 is realized by the cooperation of the processor 401 and the main storage unit 402. The reception processing unit 43 is an example of a processing unit that discards or processes the received communication data. The reception processing unit 43 includes a reception data analysis unit 431 that analyzes received communication data, and a reception buffer 432 that temporarily stores the received communication data. The reception data analysis unit 431 reads out the information included in the received communication data and determines whether or not to store the communication data in the reception buffer 432. Communication data determined to be stored by the reception data analysis unit 431 is stored in the reception buffer 432, and communication data determined not to be stored is discarded. Then, storage data is extracted from the communication data stored in the reception buffer 432, and the extracted storage data is stored in the cyclic memory 41. Although the example in which the communication data is stored in the reception buffer 432 has been described, the storage data extracted from the communication data by the reception data analysis unit 431 may be stored in the reception buffer 432.

The transmission processing unit 44 is realized by the cooperation of the processor 401 and the main storage unit 402. The transmission processing unit 44 includes a transmission data generation unit 441 that generates communication data and a transmission buffer 442 that temporarily stores communication data to be transmitted. The transmission data generation unit 441 determines whether the communication data to be transmitted is an object of cyclic communication or an exception, according to the analysis result by the reception data analysis unit 431, or by the transmission data generation unit 441 itself. decide. Then, the transmission data generation unit 441 generates communication data including the determined content and the storage data read from the cyclic memory 41, and stores the communication data in the transmission buffer 442. The communication data stored in the transmission buffer 442 is transmitted to the communication network 50 via the communication interface 42 at the timing controlled by the transmission processing unit 44. Note that the example in which the communication data is stored in the transmission buffer 442 has been described, but the storage data read from the cyclic memory 41 is stored in the transmission buffer 442, and the transmission data generation unit 441 causes the transmission data generation unit 441 to store the communication data in the transmission buffer 442. The communication data may be generated by reading the stored data.

Next, communication processing executed by the plurality of communication devices 40 will be described with reference to FIGS. The master device 10 executes the master process shown in FIG. 6, and the

slave devices

21, 22, 30 execute the slave process shown in FIG. These processes are started when the communication device 40 is powered on and becomes communicable via the communication network 50.

In the master process shown in FIG. 6, the master device 10 executes a master initialization process (step S11). The master initialization process is a process executed by the master device 10 in the initialization phase of the communication system 1000, and is a process of setting whether the master device 10 performs cyclic communication or exceptional communication. Next, the master device 10 executes a master communication process (step S12). The master communication process is a process of communicating with the

slave devices

21, 22, 30 every cycle according to the setting of the master initialization process. Details of these master initialization processing and master communication processing will be described later.

Further, the slave process shown in FIG. 7 will be described by taking the case where the slave device 30 executes it as an example. However, the slave process executed by the

slave devices

21 and 22 is the same process as the slave device 30. In the slave process, the slave device 30 executes a slave initialization process (step S21). The slave initialization process is a process executed by the slave device 30 in the initialization phase of the communication system 1000, and is a process of setting whether the slave device 30 performs cyclic communication or exceptional communication. The slave initialization process is executed in parallel with the master initialization process. Next, the slave device 30 performs a slave communication process (step S22). The slave communication process is a process of communicating with the master device 10 and the

slave devices

21 and 22 every cycle according to the setting of the slave initialization process. Details of these slave initialization processing and slave communication processing will be described later.

Next, the master initialization process and slave initialization process will be explained in order. In the master initialization process, as shown in FIG. 8, the master device 10 determines whether or not the device itself communicates according to the software process (step S111). Specifically, the transmission processing unit 44 of the master device 10 determines whether or not the communication for sharing the stored data with the other communication device 40 is accompanied by the software processing of the own device. Since software processing takes time to complete compared to hardware processing, it can be said that communication according to software processing is low-speed communication.

However, when the master device 10 includes the high-performance processor 401, high-speed communication can be performed even with software processing. Therefore, in addition to the software processing involved in communication, the master device 10 is predetermined. The determination in step S111 may be affirmed when the condition that the processor 401 of the different type is provided is satisfied. Further, even if the communication involves software processing, the determination in step S111 may be denied when the processor 401 of a predetermined type is provided. Further, in addition to the software processing involved in the communication, the determination in step S111 may be affirmed when the condition that the calculation load of the software processing is heavy to some extent is satisfied. Whether or not the calculation load is heavy may be determined by determining whether or not the size of the source code exceeds the threshold value, or whether or not the time taken in the past execution exceeds the threshold value. You may judge by.

When the master device 10 determines to communicate according to the software processing (step S111; Yes), the master device 10 notifies all slave devices that it communicates at low speed, and instructs the slave device to perform exceptional communication with itself. Yes (step S112). Specifically, the transmission processing unit 44 generates the frame 60 in the format illustrated in FIG. The frame 60 includes a header portion 61, a data portion 62, and a footer portion 63. The header portion 61 indicates a destination address 611 indicating the communication device 40 which is the transmission destination of the frame 60, a transmission source address 612 indicating the communication device 40 which is the transmission source of the frame 60, and the type of the frame 60. And frame type information 613. The data unit 62 also includes instruction information 621 indicating whether or not to instruct the

slave devices

21, 22 and 30 to perform exceptional communication. The instruction information 621 is, for example, a 1-bit flag. If the value of this flag is zero, execution of exception communication is not instructed, and each slave device may perform cyclic communication or exception communication according to the communication performance of its own device. If the value of the flag is 1, the master device 10 is notified that the speed is low, and all slave devices are instructed to perform exceptional communication.

Returning to FIG. 8, after step S112, the process executed by the master device 10 returns from the master initialization process to the master process shown in FIG.

On the other hand, when the master device 10 determines that the device is not a device that communicates according to software processing (step S111; No), the master device 10 determines whether the device 10 communicates at a lower speed than the other communication device 40 (step S111). S113). Specifically, the transmission processing unit 44 determines whether or not a parameter indicating that the master device 10 is a device that communicates at low speed is stored in the auxiliary storage unit 403 of the master device 10. This parameter may be preset when the master device 10 is shipped, or may be preset by the user. Further, the master device 10 may make a determination in step S113 by inquiring the communication performance of another communication device 40 and comparing it with the communication performance of the own device.

If the master device 10 determines that it communicates at a lower speed than the other communication device 40 (step S113; Yes), the master device 10 shifts the processing to step S112. On the other hand, when the master device 10 determines that the device is not a device that communicates at a lower speed than the other communication device 40 (step S113; No), the master device 10 provides device information regarding the

slave devices

21, 22, and 30 to each slave device. Request (step S114). Specifically, the transmission processing unit 44 generates a frame for inquiring each of the

slave devices

21, 22 and 30 as to whether to perform low speed communication or high speed communication. This frame may follow the format illustrated in FIG. When a frame of the format shown in FIG. 9 is generated, this frame will include instruction information 621 that does not instruct execution of exceptional communication. Then, the generated frame is transmitted to the

slave devices

21, 22, 30 via the communication interface 42.

Next, the master device 10 receives device information from the

slave devices

21, 22, 30 (step S115). Specifically, the reception processing unit 43 receives the response from the

slave devices

21, 22, 30 to the request in step S114 via the communication interface 42. Thereby, the master device 10 can determine whether the

slave devices

21, 22, and 30 are low-speed communication devices or high-speed communication devices, respectively.

Next, the master device 10 determines to perform exceptional communication with a slave device that communicates at a lower speed than the other communication device 40 and to perform cyclic communication with another slave device. Specifically, the reception processing unit 43 notifies the transmission processing unit 44 of the device information obtained in step S115. As a result, the transmission processing unit 44 generates a frame for cyclic communication with the

slave devices

21 and 22 that communicate at high speed, and performs exceptional communication with the slave device 30 that communicates at low speed. Generate the frame of. After that, the process by the master device 10 returns from the master initialization process to the master process shown in FIG.

In the slave initialization process executed by the slave device 30 in conjunction with the above master initialization process, as shown in FIG. 10, the slave device 30 determines whether or not there is an exception communication instruction from the master device 10. The determination is made (step S211). Specifically, the reception processing unit 43 of the slave device 30 determines whether or not the instruction of step S112 in FIG. 8 is received via the communication interface 42.

When it is determined that there is an instruction for exceptional communication from the master device 10 (step S211; Yes), the slave device 30 determines to implement exceptional communication (step S212). Accordingly, the communication data generated by the transmission processing unit 44 of the slave device 30 includes information indicating that the communication data is treated as an exception of cyclic communication. After that, the processing executed by the slave device 30 returns from the slave initialization processing to the slave processing shown in FIG. 7.

On the other hand, when it is determined that there is no exception communication instruction from the master device 10 (step S211; No), the slave device 30 determines whether there is a device information request from the master device 10 (step S213). Specifically, the reception processing unit 43 of the slave device 30 determines whether or not the data indicating the request of step S114 in FIG. 8 is received via the communication interface.

When it is determined that there is no request for device information (step S213; No), the slave device 30 repeats the determination of step S213 and waits until there is a request for device information. On the other hand, if it is determined that there is a request for device information (step S213; Yes), the slave device 30 determines whether or not the slave device 30 communicates according to software processing (step S214). This determination is the same processing as the determination in step S111 in the master initialization processing shown in FIG.

When the slave device 30 determines to communicate according to the software processing (step S214; Yes), the slave device 30 determines to perform exception communication, and returns device information indicating that the device is low speed to the master device 10. (Step S215). Specifically, the transmission processing unit 44 of the slave device 30 generates the frame 60 in the format illustrated in FIG. 11 and transmits the frame 60 via the communication interface 42. The data portion 62 of this frame 60 includes device information 622 indicating that the slave device 30 itself communicates at a low speed. The device information 622 is, for example, a 1-bit flag. If the value of this flag is zero, it indicates that the communication is low-speed, and if the value of this flag is 1, it indicates that the communication is high-speed. Returning to FIG. 10, after step S215, the process executed by the slave device 30 returns from the slave initialization process to the slave process shown in FIG. 7.

On the other hand, when the slave device 30 determines that the device is not a device that communicates according to the software processing (step S214; No), the slave device 30 determines whether the device communicates at a lower speed than the other communication device 40 (step S216). ). This determination is the same process as the determination in step S113 in the master initialization process shown in FIG.

If the slave device 30 determines that the device communicates at a lower speed than the other communication device 40 (step S216; Yes), the slave device 30 shifts the processing to step S215. On the other hand, when the slave device 30 determines that the device is not a device that communicates at a lower speed than the other communication device 40 (step S216; No), the slave device 30 determines to perform cyclic communication, and the device is high speed. The device information indicating that is transmitted as a response to the master device 10 (step S217). Specifically, the transmission processing unit 44 of the slave device 30 generates the frame 60 in the format shown in FIG. 11 and transmits the frame 60 via the communication interface 42. The data portion 62 of the frame 60 includes device information 622 indicating that the slave device 30 itself communicates at high speed. After that, the processing executed by the slave device 30 returns from the slave initialization processing to the slave processing shown in FIG. 7.

By the above master initialization process and slave initialization process, it is determined whether to perform cyclic communication or exception communication for each communication device 40. Specifically, the slave device 30 that communicates at low speed and the master device 10 that is the main communication partner perform exceptional communication, and the

other slave devices

21 and 22 and the master device 10 perform cyclic communication. To do. Here, when the master device 10 communicates at a low speed, the master device 10 and all the

slave devices

21, 22, 30 perform exceptional communication. Here, the communication device 40 that implements exceptional communication is The communication device 40 that transmits the communication data including the information indicating that the communication is to be treated as the target and transmits the communication data that includes the information indicating that the communication is to be treated as the target of the cyclic communication.

For example, when the master device 10 is a device that communicates at a low speed, as shown in FIG. 12, the master device 10 and all slave devices perform exceptional communication. Specifically, as shown in FIG. 12, the master device 10 confirms that the device itself is a device that communicates at low speed (step S31). This step S31 corresponds to the affirmative determination in step S111 and the positive determination in step S113 in the master initialization processing shown in FIG.

Next, the master device 10 notifies the

slave devices

21, 22, 30 that the master device 10 itself communicates at a low speed (step S32). Note that, in FIG. 12, only the slave device 21 is shown as a representative of the

slave devices

21, 22, and 30. This step S32 corresponds to step S112 in the master initialization process shown in FIG.

Next, the slave device 21 receives the notification in step S32 and determines to perform exceptional communication (step S33). This step S33 corresponds to step S212 in the slave initialization process shown in FIG. After that, the slave device 21 transmits / receives communication data including target information indicating an exception of cyclic communication to / from the master device 10 in the communication phase of the communication system 1000. Details of this communication phase will be described later.

In addition, for example, when the master device 10 is a device that communicates at high speed and the slave device 30 is a device that communicates at low speed, as shown in FIG. 13, the slave device 30 communicates at a low speed with itself. It is confirmed that the device is a device to be operated (step S35). This step S35 corresponds to the affirmative determination in step S214 and the affirmative determination in step S216 in the slave initialization process shown in FIG.

Next, the slave device 30 notifies the master device 10 that the slave device 30 itself communicates at a low speed (step S36). This step S36 corresponds to step S215 in the slave initialization process shown in FIG.

Next, the master device 10 receives the notification in step S36 and determines to perform exceptional communication with the slave device 30 (step S37). This step S37 corresponds to step S116 in the master initialization process shown in FIG. After that, the master device 10 transmits / receives communication data including target information indicating an exception of cyclic communication to / from the slave device 30 in the communication phase of the communication system 1000.

Next, the master communication processing executed by the master device 10 in the communication phase of the communication system 1000 will be described with reference to FIGS. In this master communication process, the master device 10 indicates, in the communication data to be transmitted, identification information indicating the cycle relating to this communication data, and whether this communication data is a target of cyclic communication or an exception. The target information and the target information are transmitted to the

slave devices

21, 22, and 30 (step S121).

Specifically, the transmission processing unit 44 of the master device 10 generates a frame 60 in the format illustrated in FIG. 15 and transmits the frame 60 via the communication interface 42. The header portion 61 of the frame 60 includes, in addition to the destination address 611, the source address 612, and the frame type information 613, identification information 614 for identifying the cycle from other cycles before and after the cycle, and the frame 60 cyclically. The target information 615 indicating whether the target of communication is an exception excluded from the target of cyclic communication. Further, the data portion 62 of the frame 60 stores storage data for updating the cyclic memory 41.

The identification information 614 is, for example, 7-bit data, and the cycle indicated by the identification information 614 is, for example, a cycle number including the time when the master device 10 transmits the frame 60. This number is a serial number and is incremented each time the cycle is updated. The cycle indicated by the identification information 614 is not limited to this, and may be changed arbitrarily.

The target information 615 is, for example, a 1-bit flag, and if the value of this flag is zero, it indicates that the frame 60 is the target of cyclic communication. If the value of this flag is 1, the frame 60 is cyclic. It indicates that this is an exception to click communication and is the target of exception communication.

Returning to FIG. 14, the master device 10 determines whether communication data has been received (step S122). Specifically, the reception processing unit 43 determines whether communication data has been received from another communication device 40 via the communication interface 42.

When it is determined that communication data has not been received (step S122; No), the master device 10 shifts the processing to step S128. On the other hand, if the master device 10 determines that the communication data is received (step S122; Yes), the target information included in the received communication data indicates that the communication data is the target of the cyclic communication. It is determined whether or not (step S123).

When it is determined that the target information does not indicate that it is the target of the cyclic communication (step S123; No), the master device 10 determines that the received communication data is the target of the exceptional communication, and the communication data Is processed (step S124). Specifically, the master device 10 processes the received communication data regardless of the cycle indicated by the identification information. Specifically, the reception processing unit 43 stores the communication data in the reception buffer 432. As a result, when the target information included in the communication data indicates that the communication data is an exception to cyclic communication, the reception processing unit 43 processes the communication data.

On the other hand, when it is determined that the target information indicates the target of cyclic communication (step S123; Yes), the master device 10 acquires the current cycle managed by the master device 10 (step S125). Specifically, the reception processing unit 43 reads the data indicating the current cycle stored in the main storage unit 402.

Next, the master device 10 determines whether the cycle indicated by the identification information included in the received communication data is equal to the current cycle acquired in step S125 (step S126). When it is determined that the cycles are equal (step S126; Yes), the master device 10 shifts the processing to step S124. On the other hand, when it is determined that the cycles are not equal (step S126; No), the master device 10 discards the received communication data (step S127). Accordingly, when the communication data that is the target of the cyclic communication is received in a cycle different from the cycle indicated by the communication data, the communication data is discarded. That is, if the target information included in the communication data indicates that the communication data is a target of cyclic communication, and if the cycle indicated by the identification information included in the communication data is different from the current cycle, reception is performed. The processing unit 43 discards the communication data.

After the end of step S124 or step S127, or if the determination in step S122 is negative, the master device 10 determines whether or not the current time is a time after which the cycle update timing has passed (step S128).

When it is determined that the current time has not passed the update timing (step S128; No), the master device 10 executes the processing of step S122 and thereafter. On the other hand, when it is determined that the current time has passed the update timing (step S128; Yes), the master device 10 updates the cycle (step S129). Specifically, the master device 10 updates the current cycle managed by itself. Thereafter, the processing by the master device 10 returns from the master communication processing shown in FIG. 14 to the master processing shown in FIG.

In the communication phase of the communication system 1000, the slave communication process shown in FIG. 7 is executed in parallel with the above master communication process. The slave communication process is the same process as the master communication process shown in FIG. However, in the slave communication process, the data transmission corresponding to step S121 may be executed at the timing when the cycle managed by the slave device 30 itself is updated, or the data reception from the master device 10 is used as a trigger. It may be executed. Also, in the procedure corresponding to step S122, the communication data determined to be received is the communication data from the master device 10 and the communication data from another slave device.

As described above, one of the master device 10 and the

slave devices

21, 22, 30 is the first communication device for transmitting communication data, and the other is the second communication device for receiving communication data. At this time, the second communication device indicates that the communication data is the target of the cyclic communication by the target information included in the received communication data, and the cycle indicated by the identification information included in the communication data is the current one. If it is different from the cycle, the communication data is discarded. The second communication device processes the communication data when the target information included in the communication data indicates that the communication data is an exception to cyclic communication. Therefore, the communication performance can be utilized while the devices having different communication performances are mixed, and the efficiency of the communication system can be improved.

Specifically, the communication device 40, which is the master device 10 or the

slave devices

21, 22, and 30, determines whether the communication data is an object of cyclic communication or an exception, and a device that transmits or receives the communication data has a low speed. Change according to whether or not to communicate with. Accordingly, in a case where the master device 10 and the slave device 21 communicate at high speed and the slave device 30 communicates at low speed, cyclic communication is performed between the master device 10 and the slave device 21, and the master device 10 and the slave device 21 communicate with each other. Exception communication is carried out between 10 and the slave device 30.

FIG. 16 illustrates the data transmission in such a case together with the contents of the identification information 614 and the target information 615. As shown in FIG. 16, since the slave device 30 has a low speed, the data transmitted from the slave device 30 in the cycle T2 may be received by the master device 10 in the cycle T3. The master device 10 can receive and process such data without discarding it. As a result, it is possible to perform communication utilizing the communication performance while mixing the communication devices 40 having different communication performances.

FIG. 17 shows a comparative example in which all communication devices 40 carry out cyclic communication. In this example, the data transmitted from the slave device 30 communicating at low speed in the cycle T2 is discarded when received by the master device 10 in the cycle T3, and as a result, the information from the slave device 30 is transmitted to the master device 10. It is not transmitted and the cyclic memory 41 is not shared between the master device 10 and the slave device 30. Therefore, there is a possibility that an inconvenience may occur in the operation of the FA system including the communication system 1000. According to the communication system 1000 according to the present embodiment, the master device 10 receives and processes the data from the slave device 30, so that it is possible to avoid the above situation.

Also, the target information indicating whether or not the communication data is the target of the cyclic communication is stored in the header part of the frame which is the communication data. Therefore, the communication device 40 that has received the communication data can determine whether or not the communication data is the target of the cyclic communication just by checking the header part even before checking the data part. it can.

It should be noted that by performing exceptional communication, it is no longer guaranteed that all communication devices 40 will be shared within each cycle, but operations that take into account that such guarantee is not made for devices that communicate at low speed. You can do it.

Also, the first communication device transmitting communication data transmits communication data including target information indicating an exception of cyclic communication, when the first communication device communicates according to software processing. Therefore, the communication data transmitted from the first communication device that communicates at a low speed is targeted for the exceptional communication, and appropriate communication data can be targeted for the exceptional communication.

Also, the first communication device transmitting communication data transmits communication data including target information indicating an exception of cyclic communication when communicating at a lower speed than other communication devices. Therefore, the communication data transmitted from the first communication device that communicates at a low speed is targeted for the exceptional communication, and appropriate communication data can be targeted for the exceptional communication.

Further, the first communication device transmitting the communication data transmits the communication data including the target information indicating the exception of the cyclic communication in response to the notification from the second communication device which is the transmission destination of the communication data. .. Specifically, the

slave devices

21, 22, 30 receive the notification of step S112 in FIG. 8 and carry out exceptional communication. Further, the master device 10 receives the device information as notification of the low speed of the

slave devices

21, 22, 30 and executes the exceptional communication as shown in step S115 in FIG. As a result, the communication partner of the communication device 40, which has a low speed, can perform exceptional communication with the communication device 40. A device that communicates at low speed may not be able to control the timing of transmission, and further may not be able to receive and process all communication data transmitted at high speed. Therefore, it is desirable that the communication partner of the communication device 40, which has a low speed, also perform the exceptional communication.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

For example, the number of communication devices 40 is not limited to the number illustrated in FIG. 1, and may be changed arbitrarily.

Also, an example has been described in which the fact that the first communication device is slow is notified by a 1-bit flag, but the invention is not limited to this. For example, the first communication device may receive a notification that the second communication device will communicate according to software processing, and may carry out exceptional communication in response to this notification. The second communication device may notify the first communication device that it communicates according to software communication. Such notification is realized by, for example, a pattern represented by a code of 2 bits or more.

Further, regarding an example in which when the master device 10 collects the device information, the

slave devices

21, 22, 30 transmit the device information and determine whether the self device performs cyclic communication or exceptional communication. Although described, it is not limited to this. For example, as shown in FIG. 18, the master device 10 instructs each slave device to perform either cyclic communication or exception communication according to the collected device information, and each slave device Cyclic communication or exception communication may be performed according to this instruction. For example, when the master device 10 indicates that one slave device communicates at a low speed by the collected device information, the master device 10 sends target information indicating that the slave device is an exception of cyclic communication to the one slave device. You may instruct to transmit the communication data containing. This instruction may be provided by a frame 60 of the type shown in FIG.

In FIG. 18, an example in which the master device 10 and the slave device 30 do not perform exceptional communication with each other and the master device 10 transmits communication data that is the target of cyclic communication to all slave devices About. The above embodiment has described the example in which the pair of communication devices that perform exceptional communication with each other are determined. However, as shown in FIG. 18, the first communication device that communicates at a low speed transmits the communication data that is the target of the exceptional communication, and the second communication device that receives this communication data is the exception of the cyclic communication. Communication data may be handled and the communication data to be subjected to cyclic communication may be transmitted to the first communication device.

Further, the communication data that is the target of the exceptional communication may not include the identification information 614. The communication device 40 that receives this communication data may process the communication data regardless of the presence or absence of the identification information 614.

The function of the communication device 40 can be realized by dedicated hardware or a normal computer system.

For example, the program P1 executed by the processor 401 is stored in a computer-readable non-transitory recording medium and distributed, and the program P1 is installed in the computer to configure an apparatus that executes the above-described processing. be able to. As such a recording medium, for example, a flexible disk, a CD-ROM (Compact Disc Read-Only Memory), a DVD (Digital Versatile Disc), and an MO (Magneto-Optical Disc) can be considered.

Alternatively, the program P1 may be stored in a disk device included in a server device on a communication network typified by the Internet, and, for example, may be superimposed on a carrier wave and downloaded to a computer.

The above processing can also be achieved by starting and executing the program P1 while transferring it through the communication network.

Further, the above-described processing can be achieved by executing all or a part of the program P1 on the server device and executing the program while the computer transmits and receives information regarding the processing via the communication network.

If the OS (Operating System) shares the functions described above, or if the OS and applications cooperate with each other, even if only the parts other than the OS are stored in the medium and distributed. Well, it may also be downloaded to your computer.

Further, the means for realizing the function of the communication device 40 is not limited to software, and a part or all thereof may be realized by dedicated hardware including a circuit.

The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Further, the above-described embodiments are for explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is not defined by the embodiments but by the claims. Various modifications made within the scope of the claims and the scope of the invention equivalent thereto are considered to be within the scope of the present invention.

The present invention is suitable for operating a plurality of communication devices having different communication performances.

1000 communication system, 10 master device, 21,22,30 slave device, 40 communication device, 41 cyclic memory, 42 communication interface, 43 reception processing unit, 431 reception data analysis unit, 432 reception buffer, 44 transmission processing unit, 441 Transmission data generation unit, 442 transmission buffer, 401 processor, 402 main storage unit, 403 auxiliary storage unit, 404 input unit, 405 output unit, 406 communication unit, 50 communication network, 60 frame, 61 header unit, 611 destination address, 612 sender address, 613 frame type information, 614 identification information, 615 target information, 62 data section, 621 instruction information, 622 device information, 63 footer section, A10, A21, A22, A30 storage area, P1 program.

Claims

A communication system having a first communication device and a second communication device for performing communication for sharing storage data stored in a storage means at a predetermined cycle,
The communication data transmitted by the first communication device is identification information that identifies a cycle relating to the communication data from other cycles before and after the cycle, and the communication data is an object of communication in each cycle, or Target information indicating whether the exception is excluded from the target,
The second communication device receives the communication data, the target information included in the received communication data indicates that the communication data is the target, and the identification information included in the communication data. When the cycle indicated by is different from the current cycle, the communication data is discarded, and when the communication information indicates that the communication data is the exception, the communication data is deleted. Processing, communication system.
The first communication device, when communicating according to software processing, transmits the communication data including the target information indicating the exception,
The communication system according to claim 1.
A communication system comprising the first communication device, the second communication device and a third communication device,
The first communication device transmits the communication data including the target information indicating the exception when communicating at a lower speed than the third communication device,
The communication system according to claim 1.
The second communication device collects device information about the first communication device, and when the collected device information indicates that the first communication device communicates at a lower speed than the third communication device, the exception Instructing the first communication device to transmit the communication data including the target information indicating that
The first communication device transmits the communication data including the target information indicating the exception, according to an instruction from the second communication device,
The communication system according to claim 3.
The first communication device transmits the communication data including the target information indicating the exception, in response to a notification from the second communication device,
The communication system according to any one of claims 1 to 4.
The second communication device notifies the first communication device to communicate according to software processing,
The communication system according to claim 5.
A communication system comprising the first communication device, the second communication device, and a fourth communication device,
The second communication device notifies the first communication device that communication is performed at a lower speed than the fourth communication device,
The communication system according to claim 5.
The communication data is a frame having a header,
The target information is included in the header,
The communication system according to any one of claims 1 to 7.
A communication device for performing communication for sharing storage data stored in a storage means with another communication device at a predetermined cycle,
Identification information indicating a cycle relating to communication data transmitted by the communication by distinguishing it from other cycles before and after the cycle, and an exception that the communication data is a target of communication in each cycle or is excluded from the target. Target information indicating whether there is, a communication interface that receives the communication data including from the other communication device,
The communication data is indicated by the target information included in the communication data indicating that the communication data is the target, and the cycle indicated by the identification information included in the communication data is different from the current cycle. And processing means for processing the communication data when the target information included in the communication data indicates that the communication data is the exception.
A communication device including.
A communication method of communicating at a predetermined cycle,
Identification information indicating a cycle relating to the data by distinguishing it from other cycles before and after the cycle, and target information indicating whether the data is a communication target for each cycle or an exception excluded from the target, Receiving the data including
When the target information included in the data indicates that the data is the target, and when the cycle indicated by the identification information included in the data is different from the current cycle, the data is discarded, Processing the data if the target information contained in the data indicates that the data is the exception;
Communication method including.
To a computer that communicates with the communication device for each predetermined cycle,
Identification information indicating a cycle relating to the data by distinguishing it from other cycles before and after the cycle, and target information indicating whether the data is a communication target for each cycle or an exception excluded from the target, Receiving the data from the communication device including
When the target information included in the data indicates that the data is the target, and when the cycle indicated by the identification information included in the data is different from the current cycle, the data is discarded, Processing the data if the target information contained in the data indicates that the data is the exception;
A program that lets you do things.